胆碱对肠系膜上动脉缺血再灌注大鼠血管损伤的影响及其分子机制

Effect of choline on ischemia reperfusion-induced vascular injury of superior mesenteric artery in rats

目的观察胆碱对肠系膜上动脉缺血再灌注(IR)大鼠血管损伤的影响,并探讨其可能的分子机制。方法选择健康雄性SD大鼠36只,随机分为假手术组、IR组和胆碱治疗组各12只。IR组建立大鼠肠系膜上动脉IR模型,胆碱治疗组根据体质量舌下静脉注射胆碱10 mg/kg后建立IR模型,假手术组仅开腹。各组分离肠系膜上动脉,HE染色后观察血管组织病理改变。收集各组腹主动脉血,采用比色法检测血清乳酸脱氢酶(LDH)水平。采用Western blotting法检测肠系膜上动脉组织PKR样内质网激酶(PERK)、磷酸化PERK(p-PERK)、免疫球结合蛋白(Bip)、磷酸腺苷激活蛋白激酶(AMPK)、磷酸化AMPK(p-AMPK)表达。结果假手术组大鼠肠系膜上动脉血管形态完整,血管内皮细胞未见异常;与假手术组比较,IR组大鼠血管内皮细胞存在空泡变性、炎性浸润,血管内皮细胞脱落;与IR组比较,胆碱治疗组大鼠肠系膜上动脉血管形态较完整,内皮细胞恢复正常,其病理改变介于假手术组和IR组之间。假手术组、IR组和胆碱治疗组血清LDH水平分别为(430.96±36.45)、(713.47±87.98)、(449.38±50.39)U/L,IR组血清LDH水平明显高于假手术组和胆碱治疗组(P均<0.05),假手术组和胆碱治疗组比较差异无统计学意义(P>0.05)。IR组大鼠肠系膜上动脉p-PERK/PERK、Bip表达均高于胆碱治疗组、假手术组,p-AMPK/AMPK低于胆碱治疗组、假手术组(P均<0.05),胆碱治疗组、假手术组上述指标比较差异均无统计学意义(P均>0.05)。三组PERK、AMPK表达比较差异均无统计学意义(P均>0.05)。结论胆碱能减轻大鼠肠系膜上动脉IR导致的血管损伤,其机制可能与抑制PERK/Bip信号通路、活化AMPK有关。

Objective To investigate the effect of choline on ischemia reperfusion(IR)-induced vascular injury of su-perior mesenteric artery in rats,and to explore the possible mechanism.Methods Thirty-six male SD rats were random-ly assigned into the following experimental groups:the sham operation group,IR group,and choline group,with 12 rats in each group.In the IR group,the mesenteric IR models were established.In the choline group,the rats were treated with choline(10 mg/kg,i.v.)10 min prior to occlusion of the superior mesenteric artery.In the sham operation group,we on-ly performed laparotomy.In each group,the mesenteric artery was isolated.After HE staining,we observed the pathologi-cal changes of the vascular tissues.The expression levels of PKR-like endoplasmic reticulum kinase(PERK),phosphory-lated PERK(p-PERK),binding immunoglobulin protein(Bip),Adenosine 5'-monophosphate(AMP)-activated protein kinase(AMPK)and phosphorylated AMPK(p-AMPK)were detected by Western blotting.At the completion of the reper-fusion procedure,arterial blood samples were collected by abdominal aortic method.Lactate dehydrogenase(LDH)activi-ty was measured by colorimetry.Result In the sham operation group,the superior mesenteric artery had complete vascu-lar morphology and no abnormalities in vascular endothelial cells were found.Compared with the sham operation group,the microstructure of the IR group appeared that the membrane of the endothelial cells was not intact,with cytoplasmic vac-uolation,inflammatory cell infiltration and elastic membrane fragmentation.Compared with the IR group,the morphology of the mesenteric artery in the choline group was more complete,the endothelial cells recovered to normal,and the patho-logical changes were between those of the sham operation group and the IR group.The LDH activity of sham operation group,IR group,and choline group were(430.96±36.45),(713.47±87.98),(449.38±50.39)U/L,respectively.The IR group had higher level of LDH as compared with sham operation group and choline group(P<0.05),and there was no significant difference between the sham operation group and choline group(P>0.05).The model rats had higher levels of p-PERK/PERK and Bip expression in the mesenteric arteries,and had significantly lower expression levels of p-AMPK/AMPK as compared with those of the sham operation group and choline group(all P<0.05);there was no significant differ-ence between the sham operation group and choline group(all P>0.05).The expression levels of PERK and AMPK were not statistically different between the three groups(all P>0.05).Conclusion Choline treatment alleviates IR-induced vascular injury of superior mesenteric artery in rats,presumably by inhibiting PERK/Bip protein expression and activating AMPK pathway.